The invention pertains to a digital circuit for classifying the frequency of a signal in at least two non-overlapping frequency ranges using the variable frequency of a clock signal as a reference.
In electronics, there is the need for a circuit which instead of measuring the variable frequency of a signal and, thus, determining the exact numerical frequency value, classifies the frequency of the signal in frequency ranges and produces a digital signal one level of which is assigned the information that the frequency lies in the associated frequency range.